In recent years, some vehicles are provided with an occupant detection system for detecting the state of occupants. As such an occupant detection system, for example, there are systems for measuring the surface temperature of an occupant with an infrared sensor and appropriately controlling air conditioning based on the measurement result. In addition, there are devices that identify an occupant through facial recognition using a camera and then enable automatic setting of a seat position or the like based on that occupant.
A vehicular air conditioner described in the following Patent Literature 1 is provided with an occupant detection system for measuring the surface temperature and position of an occupant using an infrared sensor. In this occupant detection system, the infrared sensor is disposed on a swing louver provided in a vent hole to calculate the surface temperature of the occupant. The vehicular air conditioner performs air conditioning control based on the calculated surface temperature.
In such a configuration, the direction of the infrared sensor periodically changes within a certain range in accordance with the swing of the swing louver. In other words, instead of measuring the surface temperatures of all the occupants in one measurement and at the same time, a local range is measured. As such, the entire temperature distribution is detected by gradually moving the local range while. Accordingly, it is possible to perform temperature measurement over a wide range including any occupants while using an inexpensive infrared sensor having a comparatively narrow detection range.